Here is a fantastic tool we are so fortunate to have at hand in New Zealand. It is called SOLARVIEW and is produced by NIWA. This an excellent tool for providing a early assessment of the Solar value of a particular section when you are searching for that perfect place to build your Earthship or Passive Solar Home.
So how does it work?
You simply input the street address of the section you are looking at and it will give you the Latitude and Longitude that Solarview needs. Then simple press the ‘Create solar view’.
and viola! Here is your Solar View Chart.
So what does it tell me?
Its not definitive by any stretch, as you will need to still ‘walk the ground’ and take a manual solar survey to be sure that no human-made structures obscure your sun. However it will tell you the trajectory of the sun across five points of the year covering the Summer and Winter Solstice and Autumnal and Spring Equinoxes. The 24 hour clock is shown on the underside of the arc’s andon top of each arc is the amount of solar-generated KWh per sq mtr that you could expect at each time coordinate. This is great information for assessing how many solar PV panels you would likely need to generate enough power throughout the year.
For estimates on how much power you might need to generate, check out this piece of work. Solarview is free to use and the best way to understand it is to start plugging in some addresses and looking at the charts yourself.